/*
 * ProGuard -- shrinking, optimization, obfuscation, and preverification of Java bytecode.
 *
 * Copyright (c) 2002-2018 GuardSquare NV
 *
 * This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public
 * License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later
 * version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied
 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along with this program; if not, write to the Free
 * Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */
package proguard.optimize.info;

import proguard.classfile.*;
import proguard.classfile.attribute.*;
import proguard.classfile.attribute.visitor.AttributeVisitor;
import proguard.classfile.util.SimplifiedVisitor;
import proguard.optimize.KeepMarker;

/**
 * This AttributeVisitor delegates calls for code attributes to another AttributeVisitor, but only if they can be
 * optimized.
 * <p>
 * <b>Note:</b> any other attribute will <b>not</b> be delegated.
 * </p>
 *
 * @author Thomas Neidhart
 */
public class OptimizationCodeAttributeFilter extends SimplifiedVisitor implements AttributeVisitor {
    private final AttributeVisitor attributeVisitor;
    private final AttributeVisitor otherAttributeVisitor;

    /**
     * Creates a new OptimizationCodeAttributeFilter.
     * 
     * @param attributeVisitor the <code>AttributeVisitor</code> to which visits will be delegated.
     */
    public OptimizationCodeAttributeFilter(AttributeVisitor attributeVisitor) {
        this(attributeVisitor, null);
    }

    /**
     * Creates a new OptimizationCodeAttributeFilter.
     * 
     * @param attributeVisitor the <code>AttributeVisitor</code> to which visits will be delegated if the code attribute
     *        can be optimized.
     * @param otherAttributeVisitor the <code>AttributeVisitor</code> to which visits will be delegated if the code
     *        attribute must be kept.
     */
    public OptimizationCodeAttributeFilter(AttributeVisitor attributeVisitor, AttributeVisitor otherAttributeVisitor) {
        this.attributeVisitor = attributeVisitor;
        this.otherAttributeVisitor = otherAttributeVisitor;
    }

    // Implementations for AttributeVisitor.

    public void visitAnyAttribute(Clazz clazz, Attribute attribute) {}

    public void visitCodeAttribute(Clazz clazz, Method method, CodeAttribute codeAttribute) {
        AttributeVisitor visitor = !KeepMarker.isKept(codeAttribute) ? attributeVisitor : otherAttributeVisitor;

        if (visitor != null) {
            visitor.visitCodeAttribute(clazz, method, codeAttribute);
        }
    }

}